Re: Multiple-Attribute Keys and 1NF
Date: Wed, 29 Aug 2007 05:10:40 GMT
Message-ID: <kd7Bi.868$CO5.480_at_trndny01>
"JOG" <jog_at_cs.nott.ac.uk> wrote in message
news:1188327226.729673.127810_at_r34g2000hsd.googlegroups.com...
> Okay, sure. But then to be able to query for green and yellow
It took me a while to realize that what you meant from your original
description was that
Clearly what we have here is not a domain of colors, but a domain of color
codes, where a color code contains one or more colors, and maybe a "thick
> individually one must employ a further relation encoding two more
> propositions that state "'Green and yellow' contains 'Green'" and that
> "'Green and yellow' contains 'Yellow'" respectively. One then has a
> schema with two domains - one for the composites and one for
> individual colours (which is what I was inferring when I initially
> said a new one was being added).
"a green and yellow wire means earth". I had thought you meant "a green
wire means earth" and "a yellow wire means earth". Pardon me for being
dense.
It's not clear to me why you need to able to query on simple colors, unless you need to decompose the color coding scheme into its constituent parts for some reason.
There are lot of code domains where each code is made up of a set of more
primitive elements.
B1, B2, B4, B8, B16, B32, B64, B128
Perhaps a very relevant one might be "character code". If I have the
following primitive elements:
I think that the colors, as constituents of color codes, play the same role as bits, as constituents of character codes. Do you agree? Received on Wed Aug 29 2007 - 07:10:40 CEST